Cholesterol Journal Articles

Record 3841 to 3860

Damage to liposomal lipids: protection by antioxidants and cholesterol-mediated dehydration
Samuni, A. M., A. Lipman, et al. (2000), Chem Phys Lipids 105(2): 121-34.
Abstract: Liposomes composed of egg phosphatidylcholine (EPC) (13.4%, of the acyl chains being polyunsaturated fatty acids (PUFA)) and EPC/cholesterol (10:1 mol/mol) were studied for factors that affect liposomal lipid oxidative damage and hydrolysis upon long-term (16 months) storage. Factors studied include: (1) levels of lipid/water interface hydration, related to the presence of cholesterol in the lipid bilayer; (2) the membrane-associated antioxidant vitamin E; (3) the water-soluble antioxidant Tempol; and (4) exposure to light. Liposomal dispersions were stored at room temperature, either exposed to or protected from daylight, for a period of 16 months. Chemical and physical changes were monitored at several time points to assess oxidative and hydrolytic degradation of liposomal lipids. The conclusions of the study are: (1) PUFA are the most sensitive component of the liposome bilayer to oxidative degradation damage during long-term storage; (2) EPC liposomes are more sensitive to degradation during storage than EPC cholesterol liposomes, the presence of cholesterol in the lipid bilayer having a protective effect, probably due to its effect in decreasing the lipid-bilayer hydration; (3) oxidative degradation is the major process during long-term storage, having an earlier onset than the hydrolytic degradation: and (4) Tempol provided significantly better protection than vitamin E to EPC liposomal PUFA against oxidative damage during long-term storage. The relevance of cholesterol's presence, as a 'drying agent', in membranes containing PUFA to resistance of biological membranes to oxidative damage is discussed.

Dark chocolate consumption increases HDL cholesterol concentration and chocolate fatty acids may inhibit lipid peroxidation in healthy humans
Mursu, J., S. Voutilainen, et al. (2004), Free Radic Biol Med 37(9): 1351-9.
Abstract: Cocoa powder is rich in polyphenols and, thus, may contribute to the reduction of lipid peroxidation. Our aim was to study the effects of long-term ingestion of chocolate, with differing amounts of polyphenols, on serum lipids and lipid peroxidation ex vivo and in vivo. We conducted a 3 week clinical supplementation trial of 45 nonsmoking, healthy volunteers. Participants consumed 75 g daily of either white chocolate (white chocolate, WC group), dark chocolate (dark chocolate, DC group), or dark chocolate enriched with cocoa polyphenols (high-polyphenol chocolate, HPC group). In the DC and HPC groups, an increase in serum HDL cholesterol was observed (11.4% and 13.7%, respectively), whereas in the WC group there was a small decrease (-2.9%, p < 0.001). The concentration of serum LDL diene conjugates, a marker of lipid peroxidation in vivo, decreased 11.9% in all three study groups. No changes were seen in the total antioxidant capacity of plasma, in the oxidation susceptibility of serum lipids or VLDL + LDL, or in the concentration of plasma F2-isoprostanes or hydroxy fatty acids. Cocoa polyphenols may increase the concentration of HDL cholesterol, whereas chocolate fatty acids may modify the fatty acid composition of LDL and make it more resistant to oxidative damage.

Data on cholesterol level screening of patients with ischemic heart disease in the light of the Scandinavian Simvastatin Survival Study
Mark, L., A. Kondacs, et al. (1997), Orv Hetil 138(26): 1679-82.
Abstract: The authors carried out a coronary heart disease risk factor screening on 1240 people of two villages of Bekes county, Hungary. The prevalence of coronary heart disease among the 969 people 35-70 years old was 12.0%, in the different age groups varied between 0.8 and 20.9%. This high prevalence could be explained by the high occurence of the different risk factors. The results of cholesterol levels were analysed according to that of Scandinavian Simvastatin Survival Study. From 35-70 years old screened people with coronary heart disease 77 had a cholesterol level between 5.5 and 8.0 mmol/l. In these patients with 20-40 mg daily dose of simvastatin during 5.4 years long treatment from 7 predicted coronary death 3, from 17 expected non fatal myocardial infarction 5, from 13 anticipated revascularisation procedures 5 would be preventable. The 5.4 years long treatment with 20 mg simvastatin calculated with the prices of July 1996 in Hungary would cost 292831 forints, from which 87847 has to be paid by the patient. If the decrease of hospitalization costs of the coronary heart disease patients treated with simvastatin is also taken into account, the drug treatment costs, according to the literature, could be reduced with additional 88%.

Day-to-day variability of serum cholesterol, triglyceride, and high-density lipoprotein cholesterol levels. Impact on the assessment of risk according to the National Cholesterol Education Program guidelines
Bookstein, L., S. S. Gidding, et al. (1990), Arch Intern Med 150(8): 1653-7.
Abstract: The National Cholesterol Education Program has recently published guidelines for the assessment of cardiovascular risk and goals for laboratory accuracy. To test the impact of biologic and analytic variability on the ability of a single lipid measurement to assess risk accurately, lipids were measured on three occasions in 51 volunteers. Notable day-to-day variability of total cholesterol (5%), triglyceride (20%), high-density lipoprotein cholesterol (10%), and calculated low-density lipoprotein cholesterol (8%) levels was found. Analytic variability contributed significantly to total variability of high-density lipoprotein cholesterol levels and calculated low-density lipoprotein cholesterol levels. Confidence intervals constructed around National Cholesterol Education Program cutoff points suggested that classification was reliable from a single measurement if total cholesterol value was below 4.78 (less than 185 mg/dL), between 5.56 and 5.81 (215 and 225 mg/dL), or above 6.59 mmol/L (greater than 225 mg/dL). Low-density lipoprotein cholesterol value classification from a single measurement was only accurate at below 3.00 (greater than 116 mg/dL) or above 4.50 mmol/L (greater than 174 mg/dL). This study documents significant day-to-day variability of serum lipids and suggests that patients near the National Cholesterol Education Program cutoff points may require repeated measurements to assign risk accurately.

Death rate higher in elderly with low cholesterol
SoRelle, R. (2001), Circulation 104(7): E9011-3.

Decaffeinated coffee and serum LDL-cholesterol concentrations
Pearson, T. A. (1992), Am J Clin Nutr 56(3): 604-5.

Decision rules for predicting future lipid values in screening for a cholesterol reduction clinical trial
Moye, L. A., B. R. Davis, et al. (1996), Control Clin Trials 17(6): 536-46.
Abstract: Recent large clinical trials have required screened patients to have serial measurements of an entry criteria variable, eliminating patients form further consideration if the average value is not in the eligibility range specified by the trial protocol. The increasing costs of large clinical trials required that they be executed efficiently. One way to improve efficiency would be to reduce the number of required screening measurements for a patient likely to be ineligible. A procedure is proposed that predicts the value of an average based on n measurements serially obtained on a patient during the screening phase when only m < n measurements are available. The employment of this procedure in a large clinical trial that uses low-density lipoprotein (LDL) cholesterol, total cholesterol, and triglycerides as entry criteria during the screening process is described. As a second example, this procedure is applied to population screening for lipid levels above a treatment threshold. The National Cholesterol Education Program recommends that the average of two LDL cholesterol measurements be used to determine whether LDL cholesterol is above 130 mg/dl, the threshold for treating patients with coronary heart disease. However, data from a sample of patients from a postinfarction population suggest that, if a single LDL cholesterol is above 146 mg/dl, the probability is greater than 95% that the average of the two LDL cholesterol measurements will be above 130 mg/dl.

Declaring war on undertreatment: rationale for an aggressive approach to lowering cholesterol
van Dam, M., S. van Wissen, et al. (2002), J Cardiovasc Risk 9(2): 89-95.
Abstract: Few things are better understood within the medical community than the relationship between elevated total and low-density lipoprotein cholesterol (LDL-C) levels, cardiovascular disease and death. There is consensus in the treatment guidelines of numerous national and international bodies that cholesterol levels in at-risk patients should be reduced to target levels that have been shown in population studies to be associated with low rates of coronary heart disease (CHD). However, dyslipidaemia continues to be underdiagnosed and undertreated. The 'landmark' statin trials have demonstrated unequivocally that effective lipid-lowering therapy significantly decreases CHD morbidity and mortality. Furthermore, these benefits of lipid-lowering therapy are not limited to middle-aged men, but extend across a broad range of patient populations. Recent trial data suggest that lowering LDL-C to target levels is possible in a substantial proportion of patients when statins are administered aggressively and results in a greater reduction in the risk of major coronary events. This reduction in events is seen in patients with stable coronary disease as well as those treated immediately after an acute coronary syndrome. Although strong clinical and angiographic evidence shows that intensive treatment prevents morbidity and saves lives, indications are that clinicians are still waiting too long to treat dyslipidaemia and when treatment is initiated it is often at inadequate dosages. Undertreatment of dyslipidaemia is an issue that the healthcare community can no longer ignore.

Decline in serum total cholesterol and the risk of death from cancer
Zureik, M., D. Courbon, et al. (1997), Epidemiology 8(2): 137-43.
Abstract: We investigated whether decline over time in serum cholesterol was associated with the risk of death from cancer in French men. We studied 6,230 working men, age 43-52 years in 1967-1972, who had at least three annual measurements of serum cholesterol. We estimated individual change over time in serum total cholesterol using within-person linear regression. During an average of 17 years of follow-up after the last examination, 747 subjects died from cancer. The multivariate-adjusted relative risks for subjects in the fourth (highest increase in serum total cholesterol), third, and second quartiles, compared with men in the first quartile (who had a decrease in serum total cholesterol), were 0.70 95% confidence interval (CI) = 0.56-0.87, 0.71 (95% CI = 0.57-0.88), and 0.74 (95% CI = 0.61-0.91), respectively. The group with the highest decline in cholesterol displayed an excess risk for most cancer sites. These associations were more pronounced in subjects whose weight remained stable or decreased over time than in those who gained weight.

Decline of the relative risk of death associated with low employment grade at older age: the impact of age related differences in smoking, blood pressure and plasma cholesterol
Marang-van de Mheen, P. J., M. J. Shipley, et al. (2001), J Epidemiol Community Health 55(1): 24-8.
Abstract: STUDY OBJECTIVE: To explore whether the observed age related decline in the relative risk of death associated with low employment grade can be explained by the profiles of smoking, blood pressure and plasma cholesterol changing differently with age between the employment grades. DESIGN: Prospective cohort study with 25 years of mortality follow up. SETTING: Whitehall study. PARTICIPANTS: There were 16,984 men aged 40 to 69 years at baseline with complete information on smoking, blood pressure and plasma cholesterol. MAIN RESULTS: The relative risk of death associated with low employment grade decreased from 2.1 at 55-59 years of age to 1.3 at 85-89 years of age. Adjustment for smoking status and blood pressure, attenuated the age related decline of the relative risk by 18% and 3% respectively; adjustment for plasma cholesterol increased the decline by 3%. Taken together, these risk factors explain 20% of the observed age related decline. CONCLUSIONS: A small part of the observed age related decline in the relative risk of death associated with low employment grade can be explained by differential changes in the profiles of smoking, blood pressure and plasma cholesterol with age between the employment grades.

Declining cholesterol and mortality in a sample of older nursing home residents
Grant, M. D., Z. H. Piotrowski, et al. (1996), J Am Geriatr Soc 44(1): 31-6.
Abstract: OBJECTIVE: To examine the association between declining serum cholesterol and mortality in a sample of older nursing home residents. DESIGN: A retrospective cohort study. SETTING: A 203-bed nursing home. PARTICIPANTS: Persons aged 65 and older, resident in the nursing home on January 1, 1988, or admitted through December 31, 1989, were eligible (n = 185) for the study. Follow-up for mortality was conducted until June 30, 1991. Fifty-five survivors with two or more cholesterol levels recorded before January 1, 1990, and the 76 decedents with two or more recorded cholesterol levels constituted the analytic sample (71% of eligible subjects). OUTCOME MEASURE: Mortality of the nursing home residents. RESULTS: Cholesterol declined 31.1 mg/dL/yr (95% confidence interval CI, 19.7 to 42.6) among decedents, versus 4.2 mg/dL/yr (95% CI, -4.9 to 13.2) among survivors. The association between cholesterol decline (absolute or relative rates) and mortality was examined using logistic regression controlling for age, sex, and tube feeding. Compared with a referrent group with no change or increase, declining cholesterol greater than 45 mg/dL/yr was accompanied by an adjusted relative odds for death of 6.2 (95% CI, 2.1 to 18.4); declining cholesterol greater than 20% per year was accompanied by an adjusted relative odds for death of 7.3 (95% CI; 2.4 to 22.2). Extreme declines greater than 20% per year occurred in 47% of decedents but in only 15% of survivors. CONCLUSION: Precipitously declining cholesterol appeared to be a marker for mortality in the sample and may help explain the low cholesterol-mortality association in older nursing home residents.

Declining levels of total serum cholesterol in adult New Zealanders
Skeaff, C. M., J. I. Mann, et al. (2001), N Z Med J 114(1128): 131-4.
Abstract: AIM: To measure the average serum concentration of total cholesterol and high density lipoprotein cholesterol in a representative sample of New Zealanders. METHODS: Serum total and high density lipoprotein cholesterol levels were measured in a representative sample of 1,412 men and 1,741:women aged 15 years or older who participated in the National Nutrition Survey (1997) of New Zealanders. RESULTS: The average serum total cholesterol concentration in men was the same as in women (5.7 mmol/L); however, younger women (44 years and under) tended to have lower levels and older women (55 years and over) higher levels of total cholesterol than men. Women in all age groups had higher average levels of high density lipoprotein cholesterol (1.4 mmol/L) than men (1.2 mmol/L). Ethnic differences were apparent with Maori men having significantly higher average levels of total cholesterol than their New Zealand European counterparts. CONCLUSIONS: Mean serum total cholesterol concentration in women has declined by 0.3 mmol/L from 6.0 mmol/L (p<0.05) since the previous representative survey of New Zealanders (Life in New Zealand Survey, 1989), but by only 0.1 mmol/L in men, despite a similar reduction amongst men and women in the proportion of dietary energy derived from total and saturated fat. It is possible that weight gain in men and women during the last nine years is having a differential effect on serum cholesterol concentrations.

Declining serum cholesterol levels prior to diagnosis of colon cancer. A time-trend, case-control study
Winawer, S. J., B. J. Flehinger, et al. (1990), Jama 263(15): 2083-5.
Abstract: We report the results of a 10-year, time-trend, case-control study in which serum cholesterol level was determined at several points in time preceding the diagnosis of colon cancer in a population of individuals who sought general checkups at an ambulatory care screening facility. Each of the 69 patients with colon cancer (32 men and 37 women) was matched with a control patient who was randomly selected. At the time of diagnosis, the patients with colon cancer had significantly lower serum cholesterol values than control patients (5.56 +/- 0.31 mmol/L SEM vs 6.47 +/- 0.34 mmol/L). This difference did not vary with sex or Dukes' stage of the cancer. The percent of matched pairs in which the cancer patient had a lower serum cholesterol level increased from 42% at 10 years prior to cancer diagnosis to 77% at diagnosis. The ratio of serum cholesterol at each period to the level at time of diagnosis demonstrated an average decline of 13% during the 10 years prior to diagnosis for case patients vs an average rise of 2% in the same period for control patients. We conclude that individuals in whom colorectal cancer develops share the same level of serum cholesterol as the general population initially, but during the 10 years preceding the cancer demonstrate a decline in serum cholesterol level that is opposite to the rising level seen with age in the general population.

Declining serum total cholesterol levels among US adults. The National Health and Nutrition Examination Surveys
Johnson, C. L., B. M. Rifkind, et al. (1993), Jama 269(23): 3002-8.
Abstract: OBJECTIVE--To examine the secular trend in serum total cholesterol levels of the US adult population. DESIGN--Nationally representative cross-sectional surveys with both an in person interview and a medical examination that included the measurement of blood lipid levels. SETTING/PARTICIPANTS--Between 6000 and 13,000 adults aged 20 through 74 years examined in each of four separate national surveys during 1960 through 1962, 1971 through 1974, 1976 through 1980, and 1988 through 1991. RESULTS--Mean serum total cholesterol levels in US adults aged 20 through 74 years have consistently declined over the time period 1960 through 1991. More than half of the decline occurred during the time period 1976 through 1991. This decline occurred across the entire distribution of serum cholesterol levels and in all age-sex groups. High-density lipoprotein cholesterol and very low-density lipoprotein cholesterol levels have not changed, suggesting that the decline in total cholesterol levels is due to a decline in low-density lipoprotein cholesterol levels. CONCLUSIONS--These results document a continuing and substantial decline in serum cholesterol levels among US adults. They suggest that public health programs, designed to reduce cholesterol levels, are proving successful. The observed downward trend in serum cholesterol levels has coincided with a continuing decline in coronary heart disease mortality. These observations suggest that the Healthy People 2000 goal of reducing the mean serum cholesterol level of US adults to no more than 200 mg/dL (5.17 mmol/L) is attainable.

Deconjugation of bilirubin accelerates coprecipitation of cholesterol, fatty acids, and mucin in human bile--in vitro study
Higashijima, H., H. Ichimiya, et al. (1996), J Gastroenterol 31(6): 828-35.
Abstract: To examine the initial step of brown pigment gallstone formation, sterile human gallbladder bile samples were incubated with or without beta-glucuronidase in vitro. Enhanced bilirubin deconjugation achieved by adding beta-glucuronidase significantly accelerated the formation of a precipitate that contained bilirubin (28.2 +/- 3.8% of dry weight), cholesterol (14.3 +/- 5.2%), free fatty acids (12.0 +/- 1.3%), and glycoprotein (10.0 +/- 6.7%). Both the composition and scanning electron microscopic appearance of the precipitate were similar to these features in brown pigment gallstones. The cholesterol saturation index and nucleation time in the supernatant did not change with various incubation periods. The weight ratios of bilirubin to cholesterol in the precipitates correlated with those in bile (r = 0.76; P = 0.017). Gel chromatography of the precipitate showed high molecular weight glycoprotein to be the major constituent. Bilirubin, cholesterol, fatty acids, and mucin were found to coprecipitate in accordance with bilirubin deconjugation, which process may play an important role in an early stage of the formation of brown pigment gallstones.

Decrease in cholesterol levels during the immunotherapy of cancer with interleukin-2
Lissoni, P., F. Brivio, et al. (1991), Br J Cancer 64(5): 956-8.
Abstract: IL-2, in addition to its immunomodulating and antitumour properties, induces important systemic actions, including cardiovascular, neuroendocrine and metabolic effects. The present study was carried out to evaluate IL-2 effects on cholesterol metabolism. The study included 14 advanced cancer patients (renal carcinoma: ten; colon carcinoma: four), who received IL-2 subcutaneously at a dose of 1.8 x 10(6) IU ml-2 twice daily for 5 days/week for 6 weeks. Venous blood samples were collected 7 days before, on days 0, 3, 7, 14, 21, 42 of IL-2 therapy, and on days 14 and 28 of the rest-period. IL-2 induced a rapid and evident decrease in cholesterol levels, with a normalisation of its concentrations within 7 days in 10/10 hypercholesterolemic patients. The lowest mean levels of cholesterol were reached within the first 2 weeks; after that they still slowly increased. LDL-/HDL-cholesterol ratio was significantly reduced by IL-2 therapy. Cholesterol fall was associated with a marked increase in conjugated biliary acid levels. Finally, triglyceride values increased during IL-2 therapy, but not in a significant manner. These results, by showing that IL-2 exerts an evident and very rapid cholesterol-lowering activity, would represent a further demonstration of the physiological importance of cytokines in the control of cholesterol metabolism.

Decrease in coronary heart disease mortality in 1974-1992 largely explainable by changes in cholesterol and smoking risk factors
Oei, L. T. and D. W. Erkelens (1995), Ned Tijdschr Geneeskd 139(45): 2309-14.
Abstract: OBJECTIVE. To ascertain to what extent the dramatic decrease in coronary heart disease (CHD) mortality from 1972 to the present can be attributed to a change in risk factors. DESIGN. Descriptive study based on literature data. SETTING. The Netherlands. METHODS. Changes in four risk factors were assessed: a survey on trends in average systolic and diastolic blood pressure and serum cholesterol from three national screening projects, conducted 1974-1980, among 30,000 men and women aged 37-43 years, 1981-1986 among 80,000 men aged 33-37 years, and 1987-1992 among 42,000 men and women aged 20-59 years, and the percentage of smokers observed by the Foundation on Public Health and Smoking in yearly surveys among 20,000 people from the age of 15. Using a preventable proportion calculation, the effect on mortality was estimated of the observed changes in these risk factors, applying published relative risks and regression coefficients for these risk factors for men. The estimated curves were compared with the coronary mortality curves observed by the Netherlands Central Bureau of Statistics. RESULTS. From 1974 to 1992 a substantial decrease in the percentage of smokers and in men a moderate decrease in average serum cholesterol level were observed. Serum cholesterol decreased little in women. Changes in blood pressure were not consistent. The calculations predicted a 33% decrease in CHD mortality; the decrease actually observed was 48% for men aged 20-69 and 42% for women. CONCLUSION. It appears that by far the largest proportion of the decrease in CHD mortality can be explained by a decrease in the values of relevant risk factors (cholesterol and smoking) and only a small part by improved therapy.

Decrease in fibrinogen and LDL-cholesterol levels upon supplementation of diet with Lactobacillus plantarum in subjects with moderately elevated cholesterol
Bukowska, H., J. Pieczul-Mroz, et al. (1998), Atherosclerosis 137(2): 437-8.

Decrease in high density lipoprotein binding sites is associated with decrease in intracellular cholesterol efflux in dedifferentiated aortic smooth muscle cells
Dusserre, E., M. C. Bourdillon, et al. (1994), Biochim Biophys Acta 1212(2): 235-44.
Abstract: One of the key features of atherosclerosis formation and progression is 'dedifferentiation' of contractile arterial smooth muscle cells (SMC) in synthetic cells. In primary cultures and subcultures before 10 and after 200 passages, SMC exhibit contractile-like, synthetic and transformed phenotypes, respectively, providing a good model for studying dedifferentiation process in vitro: the rationale for comparing these phenotypes of SMC in vivo rests in similar changes in cytoenzymatic and cytoskeletal features. In vivo, dedifferentiated SMC are transformed into foam cells by accumulating lipids. Thus, the aim of this study was to determine whether cholesterol metabolism undergoes changes in dedifferentiated cells and the three cultured phenotypes were compared in regard to their cholesterol efflux mechanisms. Phenotypic changes were shown to be associated with decrease in intracellular cholesterol apoprotein mediated efflux and translocation but also with decrease in high affinity binding sites for native HDL. Thus, the dedifferentiation process triggers a need for increased supply of cholesterol for membrane synthesis and efflux down-regulation mechanisms are aimed at maximizing cholesterol availability to the cell. Plasma membrane cholesterol efflux, which seems to be apoprotein-independent, decrease slightly with cell dedifferentiation suggesting either modifications in the dedifferentiated cell membranes physical properties. Taken together, these different results showed that dedifferentiation of arterial SMC is associated with decrease in the different steps of the efflux process, which could constitute one of the early events in their foam cell transformation.

Decrease in high density lipoprotein cholesterol (HDL-C) levels following gemfibrozil therapy
Lacko, A. G., B. J. Kudchodkar, et al. (1998), Clin Chem Lab Med 36(6): 389-92.
Abstract: This report represents the continuation of our studies on the effects of gemfibrozil therapy on high density lipoprotein cholesterol levels. Previously, we reported that despite an impressive mean increase in high density lipoprotein cholesterol (20%), the response to 12 weeks of gemfibrozil therapy was highly variable. Accordingly, out of the 27 subjects studied, five actually had lower high density lipoprotein cholesterol at the conclusion of therapy compared to baseline values. The changes observed in plasma lipids, combined with correlational relationships suggest that the conversion of triglyceride rich lipoprotein components into high density lipoprotein may be impaired in those subjects that respond poorly or negatively to gemfibrozil therapy.

Cholesterol Articles and Abstracts

Cholesterol Journal Articles